The present invention relates generally to communications cards and more particularly to multi-part communications card assemblies.
In many communications equipment racks, a redundancy card provides backup communications services when a primary card fails. A primary card typically has modems to provide communications services and a relay able to switch to a redundancy card if one or more of the modems fail. Thus, in the event of a failure, subscribers suffer only a brief interruption in service as the relay switches to the redundant card and the redundant card takes over communications. However, when the primary card is replaced, the subscribers potentially suffer an extended disruption of service, since the removal of the primary card removes the redundancy relay and thus severs the connection between the subscribers and the redundant card. This delay can be minimized by a quick replacement of the failed primary card with a new primary card and by ensuring that relays on the new primary card connect the subscribers to the redundant card immediately upon insertion. This allows the redundant card to provide service for the subscribers while the new board is downloaded and made available.
In accordance with the present invention, a multi-part communications card assembly is provided which substantially eliminates or reduces disadvantages and problems associated with previous card assemblies. In a particular embodiment, the present invention satisfies a need for a card assembly that allows replacement of failed communications modules while maintaining links between subscriber lines and a redundancy bus.
According to one embodiment of the present invention, a card assembly for insertion in a slot of a communications equipment rack includes a first part and a second part removably coupled to each other. The first part includes a communications module, and the second part includes a switching module. The switching module of the second part operates in a first state to couple subscriber lines to the communications module and operates in a second state to couple the subscriber lines to a redundancy bus when the first part is removed from the card assembly.
In accordance with another embodiment of the present invention, a communications equipment rack includes a backplane having a redundancy bus and a subscriber interface that couples to subscriber lines. The equipment rack also includes a network interface card coupled to a network and to the backplane. The equipment rack includes at least one card assembly having a first part that includes a communications module and a second part removably coupled to the first part, with the second part including a switching module. The switching module of the second part operates in a first state to couple selected subscriber lines to the communications module and operates in a second state to couple the selected subscriber lines to the redundancy bus when the first part is removed from the second part. In addition, the equipment rack includes at least one slot having guides for accepting each card assembly, wherein the guides facilitate the removal of a selected first part from the rack while a corresponding second part operates in the second state to couple the selected subscriber lines to the redundancy bus.
Various embodiments of the present invention provide numerous technical advantages. Multi-part communications card assemblies allow replacement of failed communications modules without disrupting service provided by backup communications cards. For example, the portion of a card assembly containing failed communications modules may be removed and replaced while another portion of the card assembly maintains a link between subscriber lines and a redundancy card. This permits modules on a card assembly having relatively high failure rates to be replaced more often than modules having relatively low failure rates. Also, by providing card assemblies for insertion in a single slot of a communications equipment rack, a single multi-part card assembly can be designed according to depth standards such as European Telecommunications Standards Institute (ETSI) standards and Competitive Local Exchange Carrier (CLEC) standards.
Other technical advantages of the present invention will be readily apparent to one skilled in the art from the following figures, descriptions, and claims.